Varcum resin

A mixture of three isomeric cresols is used in a commercially available cresol-formaldehyde Novolak resin. This mixed Novolak resin, Varcum resin (12), provides adequate properties as a host resin for near-UV- and mid-UV-photoresist applications. Gipstein and his co-workers prepared pure cresol-formaldehyde Novolak resin from each isomeric cresol and compared their spectroscopic and resist characteristics (13). Their data on the UV-absorption spectra of each cresol-formaldehyde Novolak resin together with the commercially available Varcum resin are as follows the absorbances of 0.2 jim thick Novolak films at 250 nm are 0.165(Varcum), 0.096(o-cresol), 0.092(m-cresol), and 0.055(p-cresol). The so-called "window" in the UV absorption at around 250 nm is a maximum with the p-cresol-formaldehyde Novolak resin, while the other isomeric cresol and formaldehyde Novolak resins yielded similar UV absorptions at this wavelength. The smallest UV absorption at 254 nm is an advantage for the p-cresol-formaldehyde Novolak when the resin is used for a deep UV photoresist with a suitable photoactive compound (14). 

Figure 4. UV-absorption spectra of Varcum resin (solid line), o-chloro-m-cresol-formaldehyde Novolak resin (long dotted line), and m-cresol-benzaldehyde Novolak resin (short dotted line) 0.32- thick films were...

Figure 4. Gaseous products formed in 254 nm irradiation of PMPS in Varcum resin.

Figure 7. Deep UV polymer patterns obtained with a matrix resist of poly(2-methyl-l-pentene sulfone) and Varcum resin positive tone images on the left and negative tone images on the right.

Varcum resins. Phenol-formaldehyde base resins used in plastics and var-nishes,... 

In all these studies, UV light in a region from 250 to 300 nm has been used to degrade poly(olefin sulfones) via energy transfer from the host resin in the case of composite resists with Varcum, and from sensitizers in the case of... 

Commercial products include Bakelite (Bakelite), Phenodur (Vianova Resins), Schenectady (Schenectady Chemicals), Uravar (DSM Resins). Varcum (Reichhold Chemicals). 

Varcum 564, 4326-WP, Varcum 8169, Varcum 8199. See Phenolic resin Varcum 8251, Varcum 8261, Varcum 8267. See Furan polymer... 

Varcum 29008. See Novolac resin Varcum 29413. See Phenolic resin Varcum 29419, Varcum 29427. See Novolac resin... 

Varcum 29500, Varcum 29530, Varcum 29565. See Phenolic resin Varcum 29726. See Epoxy resin Varcum 29421. See Novolac resin Varidos K-8. See Sodium sulfite Varin C. See Cocoyl hydroxyethyl imidazoline... 

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